The chairman of the Joint Chiefs of Staff on Monday pledged a thorough, transparent investigation into the deaths of four U.S. soldiers in Niger, saying they had been attacked on patrol by a group “affiliated” with the Islamic State.

“We owe you more information and, more importantly, we owe the families of the fallen more information, and that’s what the investigation is designed to identify,” Marine Gen. Joe Dunford told reporters at the Pentagon.

Story Continued Below

The investigation, he said, is being led by a general officer out of the U.S. Africa Command and will include sending personnel back to the battlefield to gather evidence.

“The questions include: Did the mission of U.S. forces change during the operation? Did our forces have adequate intelligence, equipment and training? Was our pre-mission assessment of the threat in the area accurate? How did U.S. forces become separated during the engagements, specifically Sgt. [La David] Johnson? And why did it take time to find and recover Sgt. Johnson?” Dunford said.

In an opening statement and in a lengthy question-and-answer session that followed, the Pentagon’s top general laid out what he said he knew — and didn’t know — about the Oct. 4 ambush in Niger.

Morning Defense newsletter

Sign up for Morning Defense, a daily briefing on Washington's national security apparatus.

Email

By signing up you agree to receive email newsletters or alerts from POLITICO. You can unsubscribe at any time.

His news conference came after a week of controversy over how President Donald Trump handled a condolence call to the widow of Johnson, who was killed in the ambush.

Among other details, Dunford disclosed about an hour passed from when the special operations team first took fire on Oct. 4 and when headquarters received a request for air support.

His information was necessarily incomplete, he acknowledged several times, because the U.S. Africa Command’s investigation was still underway and will be for “several weeks.”

But said he and Defense Secretary Jim Mattis, who is traveling in Asia this week, had decided he should share what they knew now to quell “speculation” about the mission and counter a “perception that the department has not been forthcoming.”

“We’ll find out in the investigation why it took them an hour,” Dunford pledged. The investigators will interview all surviving members of the team as well as French troops and others who helped rescue them, he added.

Once the air support request was received, Dunford said, a nearby U.S. surveillance drone was overhead “within minutes” and began to provide real-time video. It took another hour for French Mirage jets to arrive — half an hour for them to get off the ground and another half an hour for them to arrive over the battlefield.

Dunford also clarified that, while an ISIS-affiliated group is suspected in the attack, the Pentagon doesn’t believe the ambushers were foreign fighters.

“Our assessment right now is it is an ISIS-affiliated group,” he said. “These are local tribal fighters that are associated with ISIS.”

Dunford also offered a glimpse of the varied authorities under which special operations forces work in different parts of Africa, where he said some 6,000 American troops are deployed in 53 countries.

In Niger, he said, U.S. military advisers are not allowed to accompany local forces on missions unless “resistance is not expected,” as was the case on Oct. 4.

In Somalia, on the other hand, advisers with other special operations units may go along on missions where gunfights are expected, but they are required to stay at the “last position of cover and concealment” while their local partners move forward.

Such training-and-advising missions are important because militant groups like ISIS and Al Qaeda thrive where local governments and security forces are weak, Dunford said.

U.S. forces, he noted, have conducted training missions “off and on” in Niger for more than 20 years, and the current West Africa special operations advisory task force has existed for nearly a decade, since 2008.

With the investigation, Dunford promised equal transparency with the families of the four soldiers killed in action and with the media.

“The first thing we’re going to do is go visit the families in their homes, should they welcome us,” the general said. “As soon as we’re done with that, we’ll come back in here and share exactly the same information” with the press.

In the meantime, he said, special operations troops in Niger “are back to conducting operations as normal” with their Nigerien partners. And it’s those partners, he added, who will go after the Oct. 4 ambushers.